JP2011046576A - Fertilizer, method and apparatus for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make sludge useful as a fertilizer without disposing of it inefficiently. <P>SOLUTION: An exhaust G2 is extracted partly from a flue gas flowing in a kiln exhaust gas duct connecting an end 2a of a cement kiln 2 and the lowest cyclone 5. Dust in the exhaust gas is scrubbed with water in a wet dust collector 12 and a filter 15. An apparatus 1 for manufacturing a fertilizer includes a spray dryer 18 for drying a filtrate L2 obtained by scrubbing using an exhaust gas G3, a crushing flash dryer 10 for drying sludge W1 using the exhaust gas G3, and a granulator 19 for mixing a dried product P of the spray dryer 18 and a dried product W1 of the crushing flash dryer 10 to granulate them. A fertilizer M manufactured in the apparatus 1 for manufacturing a fertilizer includes potassium chloride (KCl) in addition to nitrogen (N) and phosphoric acid (P) contained in the dried products of the sludge, which are three elements of a fertilizer, and thus can be effectively used for growing plants. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fertilizer and a manufacturing method and a manufacturing apparatus thereof, and more particularly to a method of manufacturing a fertilizer in a cement manufacturing process while effectively using sludge.

  In recent years, the amount of sewage sludge generated has increased rapidly due to the expansion of the sewer network. The main treatment methods for sewage sludge are (1) landfill disposal as it is, (2) landfill disposal of ash after incineration, and (3) compost treatment and use for farmland, etc. However, securing landfill sites and construction of incinerators are becoming difficult, and their use on agricultural land is limited in quantity, which makes it difficult to treat them. In addition, as in the case of sewage sludge, there is a demand for the development of an effective utilization method for the treatment of sludge generated from the treatment of industrial wastewater and household wastewater.

  Therefore, Patent Document 1 describes a sludge treatment method in which fly ash is added to and mixed with a sludge / lime mixture obtained by mixing quicklime with sludge. In this method, by using fly ash that is discharged in large quantities as industrial waste from thermal power plants etc., it is possible to remove the malodor of the sludge / lime mixture at low cost, and the treated product can be treated with lime content of cement raw material, It can be used as a raw material for agricultural fertilizer.

  On the other hand, Patent Document 2 proposes a method for producing a raw material for cement production from sewage sludge, in which the amount of quicklime is appropriately adjusted by simple means and the moisture content of the dry powder can be kept constant. In this method, the quicklime supply amount is automatically adjusted so that the temperature inside the aging machine becomes a target value determined by the moisture content of the obtained dry powder. For this reason, a dry powder having a desired moisture content can be obtained, and the powder can be easily used as a cement raw material.

  Conventionally, in cement factories, sludge such as sewage sludge is directly put into a cement firing device (see Patent Document 3), or sludge is dried with cement kiln exhaust gas and then put into a cement firing device (patent). Reference 4).

JP-A-8-206700 JP-A-11-35353 JP-A-8-276199 International Publication WO2008 / 001746

  However, in the methods described in Patent Documents 1 and 2, since fly ash or quick lime is added to sludge, there is a problem that a device for transporting and adding them and an operation cost are required.

  On the other hand, when the sludge is directly used as a raw material in a cement burning apparatus in a cement factory, there is no cost for adding other substances unlike the methods described in Patent Documents 1 and 2. However, since sludge has a large amount of moisture of about 80% and has a small amount of ash, the sludge is thrown into the cement baking equipment rather than simply being reused as a cement raw material. However, considering the heat of drying for evaporating the water in the sludge, it was not an efficient treatment method.

  Then, this invention is made | formed in view of the problem in the said prior art, Comprising: It aims at making effective use as a fertilizer, without disposing sludge inefficiently.

  In order to achieve the above object, the present invention is a fertilizer, and is characterized by mixing dried sludge and potassium chloride. Since this fertilizer contains potassium chloride (KCl) in addition to nitrogen (N) and phosphoric acid (P) contained in the dried sludge, it has three elements of fertilizer and can be used effectively for plant growth. it can. Moreover, the said mixture can be granulated and can be used as a granular fertilizer. Here, the sludge includes various sludges such as sewage sludge, human waste sludge, and food industry wastewater sludge.

  Moreover, this invention is a fertilizer manufacturing method, Comprising: Sludge is dried using the waste heat of a cement manufacturing process, This dried sludge and potassium chloride are mixed. Thereby, an inexpensive fertilizer provided with the above three elements can be provided. At this time, as the waste heat, the heat of a part of the combustion gas extracted from the kiln exhaust gas flow path from the bottom of the kiln of the cement kiln to the lowermost cyclone can be used, for example, attached to the cement kiln. A chlorine bypass system is available.

  Furthermore, in the fertilizer manufacturing method, the potassium chloride can be recovered from the cement manufacturing process, and a part of the combustion gas extracted from the kiln exhaust gas flow path from the bottom of the cement kiln to the bottom cyclone is cooled. The dust generated by the cooling, that is, the chlorine bypass dust is classified, the fine powder obtained by the classification is washed with water, and the filtrate obtained by the washing is dried to obtain a dried product as the potassium chloride source. be able to. Thereby, while being able to provide a cheaper fertilizer, the effective utilization of chlorine bypass dust can be aimed at.

  Further, the present invention is a fertilizer manufacturing apparatus, a water washing apparatus for washing dust in gas extracted from a kiln exhaust gas flow path from the kiln bottom of a cement kiln to the lowest cyclone, A first drying device for drying the filtrate after washing with the water washing device using the extracted gas, a second drying device for drying sludge using the extracted gas, and the first and first And a granulating device for mixing and granulating the dried material by the drying device. According to the present invention, similarly to the above-described invention, an inexpensive fertilizer having three elements can be provided by using a chlorine bypass system attached to a cement kiln.

  Furthermore, in the fertilizer manufacturing apparatus, the first drying apparatus can dry the filtrate by bringing the air heated by using the extracted gas into direct contact with the filtrate. Thereby, mixing with the fertilizer of the selenium (Se) and sulfur oxide (SOx) contained in the extracted gas can be prevented, and a higher quality fertilizer can be obtained.

  As described above, according to the present invention, it is possible to manufacture fertilizer while effectively using sludge without disposing sludge inefficiently.

It is a figure which shows 1st Embodiment of the fertilizer manufacturing apparatus concerning this invention. It is a figure which shows 2nd Embodiment of the fertilizer manufacturing apparatus concerning this invention.

  Next, modes for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows a first embodiment of a fertilizer manufacturing apparatus according to the present invention. This fertilizer manufacturing apparatus 1 uses a chlorine bypass system attached to a cement kiln 2 and extracts a part of combustion gas from a kiln bottom 2a of the cement kiln 2 and cools the extracted gas to a cooling fan (not shown). ), The probe 4 cooled by the cold air introduced from the above, the cyclone 6 for classifying the dust contained in the extracted gas G1 extracted by the probe 4, and the high-temperature bag filter for collecting the fine powder D2 contained in the exhaust gas G2 of the cyclone 6 7 and the crushed air dryer 10 for drying the sludge W1 with the exhaust gas G3 of the high-temperature bag filter 7, and the dried product DW in the exhaust gas G4 of the crushed air dryer 10 is classified into the sludge dried product W2 and the fine powder D3 containing selenium. , A wet dust collector 12 that wet-collects the exhaust gas G5 (+ fine powder D3) of the cyclone 11, and a soot discharged from the wet dust collector 12. A filter 15 for solid-liquid separation of Lee S2, a salt wastewater treatment device 16 for performing treatment for obtaining potassium chloride (KCl) from the filtrate L1 discharged from the filter 15, and a treatment product T by the salt wastewater treatment device 16 A filter press 17 for solid-liquid separation, a spray dryer 18 for drying the filtrate L2 from the filter press 17 by the exhaust G3 of the high-temperature bag filter 7, a dried product P of the spray dryer 18, and a sludge dried product from the cyclone 11 It is composed of a granulating device 19 and the like for mixing and granulating W2.

  The probe 4 and the cyclone 6 have the same configuration as that installed in a general chlorine bypass facility, and detailed description thereof will be omitted.

  The high-temperature bag filter 7 is provided for collecting the exhaust gas G2 (+ fine powder D2) from the cyclone 6, and is, for example, a bag filter provided with a ceramic filter and having a heat resistance up to about 900 ° C. This is a solid-gas separation device. Various types of high-temperature bag filters 7 have been developed, such as those in which a plurality of rod-shaped ceramic tubes (ceramic filters) formed into honeycomb cells are arranged, and those using sheet-shaped ceramic filters.

  The crushing air dryer 10 is provided to dry the sludge W1 with the exhaust gas G3 supplied from the high-temperature bag filter 7 through the blower 9 while crushing the sludge W1. The crushing air dryer 10 is, for example, a chain blow type dryer, and although not shown in the drawings, the sludge W1 and the exhaust gas are provided with a supply port for the sludge W1 at the top and a supply port for the exhaust gas G3 at the bottom. G3 is contacted in countercurrent. In addition, a rotation shaft and a striking chain that extends and rotates in the horizontal direction by centrifugal force as the rotation shaft rotates are provided inside. Instead of the chain striking type crushing air dryer 10, a rod hitting type, cage mill type or swivel type drier having a round bar attached horizontally instead of the chain can be used.

  The wet dust collector 12 collects the fine powder D3 containing selenium in the exhaust gas G5 of the cyclone 11 and also the fine powder D2 having a high chlorine content collected by the high-temperature bag filter 7 and supplied through the feeder 8 with water. The scrubber 12a, the circulating liquid tank 12b, and the washing tower 12c are provided. A circulation pump 13 for circulating the slurry S1 discharged from the circulation liquid tank 12b in the wet dust collector 12 is provided between the scrubber 12a and the circulation liquid tank 12b.

  The filter 15 is provided for solid-liquid separation of the slurry S2 supplied from the wet dust collector 12 into the filtrate L1 and the cake C1, and the filter 15 is cleaned for cleaning organic substances in the slurry S2. Water is supplied, and the inside of the filter 15 is sucked by the exhaust fan 14 through the cleaning tower 12c.

  The salt wastewater treatment device 16 is provided to remove organic substances and heavy metals contained in the filtrate L1 supplied from the filter 15, and includes a plurality of chemical reaction tanks (not shown). The filter press 17 is provided for solid-liquid separation of the product T processed by the salt wastewater treatment device 16 into a filtrate L2 containing potassium chloride (KCL) and a cake C2 containing heavy metals.

  The spray dryer 18 is provided to dry the filtrate L2 from the filter press 17 with the exhaust gas G3 from the high-temperature bag filter 7. Although not shown in the following, the atomization device, the hot air introduction device, the drying chamber, and the dry powder are omitted. A separation and collection device, an exhaust treatment device, and a product cooling device are provided. The atomization device sprays the filtrate L2 with a nozzle, and the hot air introduction device is a device that introduces the exhaust gas G3 into the drying chamber.

  The granulating device 19 is provided to obtain the fertilizer M by mixing and granulating the dried material P containing potassium chloride discharged from the spray dryer 17 and the sludge dried material W2 from the cyclone 11.

  Next, operation | movement of the fertilizer manufacturing apparatus 1 which has the said structure is demonstrated, referring FIG.

  A part of the combustion gas is extracted from the kiln bottom 2a of the cement kiln 2 by the probe 4, and at the same time, rapidly cooled to 700 ° C. or lower, which is the melting point of the chlorine compound, by cold air from a cooling fan. Next, in the cyclone 6, the extracted gas G1 exhausted from the probe 4 is separated into the coarse powder D1 and the exhaust gas G2 containing the fine powder D2, and the coarse powder D1 is returned to the cement kiln system.

  An exhaust gas G2 of about 500 ° C. is introduced into the high-temperature bag filter 7, and the exhaust gas G2 is solid-gas separated at the same temperature. In the high-temperature bag filter 7, the fine powder D <b> 2 in the exhaust gas G <b> 2 is collected and conveyed to the wet dust collector 12 through the supply device 8. Further, the blower 9 attracts the exhaust gas G3 of the high-temperature bag filter 7 and supplies it to the crushed air dryer 10 and the spray dryer 18. The exhaust gas G3 contains SOx and gaseous selenium.

  The sludge W1 is supplied to the upper part of the crushing air dryer 10, and the exhaust gas G3 is introduced from the lower part to dry the sludge W1. In the crushing air dryer 10, the sludge W1 and the exhaust gas G3 are in direct contact with each other in direct flow, and the sludge W1 is efficiently dried because the sludge W1 is dried while being crushed by a striking chain provided inside the crushing air dryer 10. Can be dried well.

  The exhaust gas G4 discharged from the crushing air dryer 10 is supplied to the cyclone 11, and the dried product DW in the exhaust gas G4 is classified into the sludge dried product W2, fine powder D3 containing selenium, and the like. The dried sludge W2 is conveyed to the granulator 19 and the exhaust gas G5 and the fine powder D3 are introduced into the wet dust collector 12.

Next, the exhaust gas G5 and the fine powder D3 are supplied to the scrubber 12a of the wet dust collector 12, and the fine powder D2 is supplied from the supply device 8, and the fine powder D3 containing selenium in the exhaust gas G5 is recovered and washed with water. I do. Here, in the slurry S1 circulating in the wet dust collector 12, Ca (OH) ₂ produced by the reaction of CaO in the fine powder D2 with water is present, so SO ₂ present in the exhaust gas G5 is added to this Ca. It reacts with (OH) ₂ and is desulfurized to produce gypsum (CaSO ₄ .2H ₂ O).

  The slurry S2 discharged from the wet dust collector 12 is subjected to solid-liquid separation after adding organic cleaning water in the filter 15. Here, the fine powder D3 containing selenium contained in the slurry S2 is discharged out of the system as a cake C1 while being contained in gypsum. On the other hand, the filtrate L1 containing potassium chloride is supplied to the salt wastewater treatment device 16. The inside of the filter 15 is sucked by the exhaust fan 14 through the cleaning tower 12c, and the odor of the filter 15 is deodorized by the cleaning tower 12c.

  In the salt drainage treatment device 16, a sulfurizing agent such as sodium hydrosulfide (NaSH) was added to the filtrate L1, and lead and thallium in the filtrate L1 were sulfided to form sulfides, thereby precipitating heavy metals. Thereafter, the filter press 17 separates the cake C2 into the filtrate L2. The cake C2 containing heavy metals such as lead sulfide and thallium sulfide is reused as a cement raw material.

  Next, the filtrate L2 from the filter press 17 is supplied to the spray dryer 18 into which the exhaust gas G3 is introduced from the high-temperature bag filter 7, and the filtrate L2 is sprayed at a predetermined nozzle pressure and dried with the exhaust gas G3.

  Finally, in the granulating apparatus 19, the dried product P containing potassium chloride from the spray dryer 18 and the sludge dried product W2 classified by the cyclone 11 are mixed and granulated to obtain the fertilizer M.

  Since this fertilizer M contains potassium chloride in addition to nitrogen (N) and phosphoric acid (P) contained in the sludge dried product W2, it has three elements of fertilizer and can be used effectively for plant growth.

  Next, 2nd Embodiment of the fertilizer manufacturing apparatus concerning this invention is described, referring FIG.

  Since this fertilizer manufacturing apparatus 31 adds the indirect heater 32 to the said fertilizer manufacturing apparatus 1, and it is the same as that of the fertilizer manufacturing apparatus 1 about another structure, about the same component as the fertilizer manufacturing apparatus 1 in FIG. Are denoted by the same reference numerals, and the description thereof is omitted.

  In this fertilizer manufacturing apparatus 31, the high temperature exhaust gas G3 from the suction fan 9 is not used for drying the filtrate L2 by the spray dryer 18, but the air is indirectly heated by the exhaust gas G3 using the indirect heater 32 and heated. Hot air HG is used. The exhaust gas G3 discharged from the indirect heater 32 is introduced into the wet dust collector 12 and processed.

  With the above configuration, selenium and SOx contained in the exhaust gas G3 can be prevented from entering the spray dryer 18, and they do not enter the dry matter P, leading to an improvement in the quality of the fertilizer M. Furthermore, since SOx is not included in the exhaust from the spray dryer 18, it can be released to the atmosphere without desulfurization.

  In addition, in the said embodiment, although the case where the fertilizer M was manufactured using the chlorine bypass system attached to the cement kiln 2 was demonstrated, sludge W1 using facilities other than the chlorine bypass system of a cement manufacturing process. Can be dried and mixed with a substance containing potassium chloride to produce a fertilizer, or the fertilizer can be produced using a process other than the cement production process.

DESCRIPTION OF SYMBOLS 1 Fertilizer manufacturing apparatus 2 Cement kiln 2a Kiln bottom 4 Probe 5 Bottom cyclone 6 Cyclone 7 High temperature bag filter 8 Feeder 9 Blower 10 Crushing air dryer 11 Cyclone 12 Wet dust collector 12a Scrubber 12b Circulating liquid tank 12c Washing tower 13 Circulating pump 14 Exhaust fan 15 Filter 16 Salt waste water treatment device 17 Filter press 18 Spray dryer 19 Granulator 31 Fertilizer production device 32 Indirect heater C1, C2 Cake D1 Coarse powder D2, D3 Fine powder DW Dry matter G1-G5 Exhaust gas HG Hot air L1, L2 Filtrate M Fertilizer P Dry matter S1, S2 Slurry T Processed matter W1 Sludge W2 Sludge dry matter

Claims (8)

  A fertilizer characterized by mixing dried sludge and potassium chloride.   The fertilizer according to claim 1, wherein the mixture is granulated. Use the waste heat from the cement manufacturing process to dry the sludge,
The fertilizer manufacturing method characterized by mixing this dried sludge and potassium chloride.   The fertilizer manufacturing method according to claim 3, wherein the waste heat is heat of a part of the combustion gas extracted from the kiln exhaust gas passage from the kiln bottom of the cement kiln to the lowermost cyclone.   The fertilizer manufacturing method according to claim 3 or 4, wherein the potassium chloride is recovered from a cement manufacturing process. A part of the combustion gas extracted from the kiln exhaust gas flow path from the bottom of the cement kiln to the bottom cyclone is cooled,
Classifying the dust generated by the cooling;
The fine powder obtained by the classification is washed with water,
The fertilizer manufacturing method according to claim 3, 4 or 5, wherein a dried product obtained by drying the filtrate obtained by the water washing is used as the potassium chloride source. A water washing device for washing dust in the gas extracted from the kiln exhaust gas flow path from the kiln bottom of the cement kiln to the bottom cyclone,
A first drying device for drying the filtrate after washing with the water washing device using the extracted gas;
A second drying device for drying sludge using the extracted gas;
A fertilizer manufacturing apparatus, comprising: a granulating device that mixes and granulates the dried material by the first and second drying devices.   The fertilizer manufacturing device according to claim 7, wherein the first drying device dries the filtrate by bringing the air heated by using the extracted gas into direct contact with the filtrate.

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